Electromagnetic contactor

ABSTRACT

A small type electromagnetic contactor including a pivot-less carrier for a movable core adapted for stable magnetic coupling to a fixed core and to easy-assembly structure. The movable core substantially of rectangular body and having a reverse U-shaped section has at the lower end of both legs a lateral inward and outward extension so as to provide a downward groove in the body of substantial T-shape. The carrier includes an upward projection of a substantially complementary shape to the T-shaped groove of the core, and the core is resiliently mounted on the carrier projection. The carrier holds in its body a plurality of resiliently movable contacts. Fixed contacts to oppose these movable contacts are arranged in arrays within an insulating box separated from each other by walls of the box. An insulating lock means is mounted on the fixed contacts to lock them in a fixed position.

United States Patent Kiyoshi 51 Mar. 21, 1972 [54] ELECTROMAGNETICCONTACTOR [72] Inventor: Yamada Kiyoshi, Kadoma, Japan [73] Assignee:Matsushita Electric Works, Ltd., Osaka,

'Japan [22] Filed: Mar. 19, 1971 211 Appl. No.: 125,950

Primary Examiner-Harold Broome Attorney-Pierce, Schefi'ler & Parker [57]ABSTRACT A small type electromagnetic contactor including a pivot-lesscarrier for a movable core adapted for stable magnetic coupling to afixed core and to easy-assembly structure. The movable coresubstantially of rectangular body and having a reverse U-shaped sectionhas at the lower end of both legs a lateral inward and outward extensionso as to provide a downward groove in the body of substantial T-shape.The carrier includes an upward projection of a substantiallycomplementary shape to the T-shaped groove of the core, and the core isresiliently mounted on the carrier projection. The carrier holds in itsbody ,a plurality of resiliently movable contacts. Fixed contacts tooppose these movable contacts are arranged in arrays within aninsulating box separated from each other by walls of the box. Aninsulating lock means is mounted on the fixed contacts to lock them in afixed position.

4 Claims, 5 Drawing Figures PATENTEDHARZI I972 SHEET 2 BF 4 n m I I n vr V w 27 ELECTROMAGNETIC CONTACTOR This invention relates toelectromagnetic contactors of small type.

There have already been suggested electromagnetic contactors of suchstructure that a plurality of opening and closing elements respectivelycomprising movable contacts and fixed contacts arecontained in aplurality of opening and closing chambers, which elements are opened andclosed by means of an operating lever or a carrier coupled to anelectromagnet. In those electromagnetic contactors of the type referredto, there have been involved various defects in that contact between theopening and closing elements becomes unstable due to such reasons as thefixed contacts are loosened after repeated vibrations, level differenceat contacting position is caused to occur due to dimensional error sothat proper contacting clearance cannot be obtained, or the like.Further, the conventional operating lever has been of such type that itsrespective ends are engaged with the movable core and then pivoted. Insuch type, however, there have been involved such defects that theengaging section of the lever has had to occupy a large percentage ofthe whole volume, the pivoting has required a suitable jig, the wear inthe structure has been so great that its life has been short and so on.The present invention has been suggested to remove such defects asabove.

A principal object of the present invention is, therefore, to provide anelectromagnetic contactor of a small type and yet has a high performanceand which is easy to manufacture.

Another object of the present invention is to provide an electromagneticcontactor having a movable core which is adapted to be of lightweight,long life and low noise type and is formed in a unique shape.

A further object of the present invention is to provide anelectromagnetic contactor in which the engagement of the operating leverfor opening and closing contacts -with the movable core is not of thepivot type so that the same is easy and rapid and the core is preventedfrom being inclined so as to carry out stable operation.

Afurther object of the present invention is to provide anelectromagnetic contactor in which any loosening at coupling sectionsbetween respective parts due to mechanical vibrations of fixed contactsat the time of contact opening and closing or shocks at the time ofconnecting external terminals thereto is prevented from occurring.

It is a still further object of the present invention to provide anelectromagnetic contactorof the type that the fixed contacts can bearranged in an array at predetermined positions.

The present invention shall be explained in detail with reference toaccompanying drawings, in which:

FIG. 1 is a side elevation of the electromagnetic contactor according tothe present invention. 7

FIG. 2 is a cross section substantially at the center of the contactorshown in FIG. 1.

FIG. 3 is a perspective exploded view of respective parts exceptcovering case of the contactor of the present invention.

FIG. 4 is a perspective view showing bottom side of coil block of thecontactor of the invention.

FIG. 5 is a fragmentary vertical section taken along line V- V in FIG. 2showing the structure of the contactor.

While the present invention will be set forth with reference to theparticular embodiment as illustrated, it is not the intention to limitthe invention to such particular embodiment, but rather to include allpossible modifications, alternatives and equivalent arrangements withinthe scope of the appended claims.

Referring now to the drawings, 1 is an E-shape fixed core, 1 is a coilblock,'and 3 isa coil'bobbin which is engaged in recessed sections ofsaid E-shape fixed core 2. At the bottom surface of said coil bobbin,there is provided a guide wall 4 (FIG. 4), which in turn is providedwith semicircular stubs 5 at both opposed endwise sides. 6 is anauxiliary core, which has an aperture 7 at the central raised part andrecesses 8 at both longitudinal endwise edges of the aperture 7. 2 is amoving core, which comprises a substantially U-shaped body part 10having at its respective legs 11 lateral extensions 12 so as to form asubstantially T-shaped load-engaging groove 13. For the material of themoving core}, a rod shaped metal having high magnetic characteristicsmay be cut to form the core, or a sintered alloy material may be used.12 is a, carrier made of an electrically insulating material andprovided with an engaging projection 14 substantially of T-shape insection and dimensioned so as to be relatively smaller than saidload-engaging groove 13 of the moving core 9. The upper surface of saidengaging projection 14 is formed to have a wavy recess 15. The carrier19 is further provided on its upper surface with a pair of receptacles17 for coil springs 16. In the main body of the carrier 12, there areprovided a plurality of openings 18, in each of which a moving contact20 is inserted, which is urged upward by means of a coil spring 21inserted between lower surface of the contact 20 and lower edge of theopening 18. 22 is a pair of fixed contacts, which are respectivelyarranged so as to oppose each of contact points of the moving contact20.

Since the carrier L2 in the illustrated embodiment is shown to have fouropenings 18, a total of four moving contacts 20 are arranged in thecarrier 12 and four pairs of the fixed contacts 22 are coupled withthese moving contacts 20. In FIG. 3 only one of the moving contacts 20and a single pair of the fixed contacts 22 are illustrated for thepurpose of simplicity.

The above mentioned fixed contacts 22 are installed in a switch box 23made of an insulating material such as a synthetic resin. 24 is alongitudinally extending space or chamber, which is provided with aplurality of switching chambers 25 arranged at both sides of the chamber24 and open at the center, respectively. 26 are grooves made in each ofthe walls 31 defining the switching chambers 25 and in alignment witheach other so as to connect the respective chambers 25 on each side ofthe chamber 24. Each of the aforementioned pair of fixed contacts 22 isreceived in each of said switching chambers 25. Lower end 27 of each ofthe pair of fixed contacts 22 is extended through the bottom section ofthe box 23 so as to extend outwardly to form terminals arranged inparallel relation to each other. 28 is a pair of insulating lock plates,each of which is provided at its lower edge with downwardly projectingparts 29 and recessed parts 30.

The projecting parts 29 extend between the adjacent walls 31 and therecessed parts 30 engage the bottoms of the grooves 26. The lock plates28 are respectively thus inserted in the grooves 26 in the respectivesides of the space chamber 24. The walls 31 are further providedrespectively at their inner end portions with Y-shaped guide sections32, which engage triangular projections 33 provided on both sidesurfaces of the carrier 12. 34 is a V-shaped plate spring, which isinserted in the space between the U-shaped load-engaging groove 13 ofmoving core 2 and the V-shaped recess 15 of the carrier 12 and isadaptedto prevent undesirable chattering of the moving core 2 when thesame is engaged with the carrier 12 as detailed later. 35 shown at thetop in FIG. 3 is an arcuate plate spring to be inserted between the topof the fixed core I and upper wall of a metal case 36 to enclose theabove structure (FIG. 2).

In assembling the electromagnetic contactor of the present invention asset forth above, the coil is nested between the side leg 38 and centerlegs 39 of the -shaped core 1 and the auxiliary core 6 is then buttedagainst the lower faces of the coil & and the side legs 38 of thecore 1. At this time, the lower end guide wall 4 of the coil bobbin 3 isengaged in the aperture 7 of the auxiliary core 6 and, at the same time,the semicircular stubs 5 of the bobbin 3 are received in the recesses 8of the core 6. Then, the engaging projection 14 provided above thecarrier 19 is inserted longitudinally into the load-engaging groove 13of the moving core B. At this time, inner edges of the lateralextensions 12 of the core 2 engage grooves 40 of the projection 14 andthe V-shaped plate spring 34 is interposed between the top surface ofthe groove 13 in the core and the upper surface of the projection 14 soas to rest in the V-shaped recess 15. The moving contacts 20 arerespectively inserted in each of the openings 18 of the carrier togetherwith the coil springs 21 respectively interposed between central lowersurface of the contact 20 and lower edge of the opening 18. The carrier12 together with the moving core 2 and the moving contacts 20 as notedabove is then inserted in the chamber 24 in the switching box 23. Then,the side wall projections 33 of the carrier 12 are engaged respectivelyin the guide sections 32 provided dii'the walls 31 in the box 23. Thefixed contacts 22 are respectively installed in the switching chambers25 with their lower ends 27 inserted in slitlike holes provided in thebottom of these chambers 25. The insulating lock plate 28 is bridgedacross and over respective walls 31 so that the recessed parts 30 willbe engaged in the array of the slots 26 and the projecting parts 29 willbutt against head section of each of the fixed contacts 22 so as to lockthe contacts 22 in their fixed position. Further, the coil springs 16are placed in receptacles l7 therefor on the carrier H, and the assemblyof the E-shaped core 1, coil 1 and auxiliary core 6 is placed on theouter periphery of the switching box 23, whereby the springs 16 arepressed downwardly by the lower surface of the core 6 and, thus, thecarrier '12 is urged downwardly against the bottom of 24. Thus, it willbe appreciated that the moving core 2, as well as the moving contacts20, are urged to rest in their normal nonoperative position. Theauxiliary core 6 is provided at its periphery with a plurality ofrecesses 43 and, on the other hand, the periphery of the box 23 isprovided with a corresponding number of bosses 44 to engage in therecesses 43 when the core 6 is placed in position. The case 26 is placedover the assembly with an interposition of the plate spring 35 at thetop position of the core 1, so as to urge the whole structure in thethus assembled position. By means of bent sections 37 urged intorecessed sections 42 in the box at the lower edge of the case 36, thecase is fixed to the box 23.

With the above arrangement, the present invention performs such variousfeatures as follows.

Since the moving core 2 of the electromagnetic contactor according tothe present iiivention is formed to have a lateral extension 12 at eachof the legs 11 of the substantially U- shaped body part so as to formthe substantially T-shaped load engaging groove 13, the moving core mayoppose the auxiliary core 6 with a sufficiently wide area of the lateralextensions 12 which are enclosed inside the central raised portion ofthe auxiliary core 6, so that the contactor can provide a higher output.In addition, the moving core 9 is adapted to hold the carrier 19 in thehollow section such as the U-shaped groove 13 and thus the moving corecan be made to be of a light weight. Further, selecting the longitudinallength] of the moving core 2 (FIG. 3) to be of any desired value, it ispossible to obtain a contactor having a moving core of suitabledimension for the required output.

In the electromagnetic contactor according to the present invention,further, the carrier 19 is provided at its top with the engagingprojection 14 having the upwardly directed V- shaped recess 15, and themoving core 2 is formed to have the above mentioned groove 13 whichengages said projection 14 so as to hold the latter therein, and theV-shaped plate spring 34 is enclosed in the space between upper insidesurface of the groove 13 and the V-shaped recess 15. Because of thisarrangement, the assembly work of the carrier and moving core is veryeasy. At the same time, the V-shaped plate spring 34 inserted betweenthese two components serves to insure that the moving core is alwayssubjected to the magnetic attraction at its proper and correct areaseven when there occurs certain inclination of the core and carrier, sothat the contactor will perform its operation without any troubleregardless of any fluctuation in positional relationship between them.

Further in the electromagnetic contactor according to the presentinvention, it is possible to minimize the size of the whole structure ofthe contactor and its assembly can be carried out very quickly whilemaintaining desired accuracy of mutual positional relationships betweenthe respective component elements, since the E-shaped fixed core 1 andthe switching box 23 arranged respectively above and below the auxiliarycore 6 are mounted and fixed in the metal case 36 through thecompression plate spring 35, while the coil block 2 bearing the E-shapedfixed core 1 is coupled to the auxiliary core 6 with the guide wall 4 atbottom surface of the bobbin 3 as engaged in the central aperture 7 ofthe core 6, and at the same time the auxiliary core 6 is positionedabove the box 23 as its peripheral recesses 43 engage the bosses 44 ofthe box 23, as well as the above discussed engaging feature of the core2 and the carrier 19, so that all the elements are assembled with eachother without requiring any special fixing means.

The present invention is further featured in that, since the fixedcontacts 22 are fixed to the bottom of the switching box 23 and theinsulating lock plates 28 are inserted between upper part of thesecontacts 22 and the auxiliary core 6 covering the switching box 23, thefixed contacts 22 are locked by means of these plates 28 against upwardmovement due to mechanical shocks thereto when the movable contacts 20,resiliently secured in the carrier 19, are urged into contact with thefixed contacts 22 by the actuation of the electromagnetic means. Thelock plates 28 are also effective in preventing any level differencefrom occurring between the various fixed contacts 22.

What is claimed is:

1. In the electromagnetic contactor, the combination comprising E-shapedfixed core having both side legs longer than a center leg, a coil blockwound around said center leg of the E- shaped fixed core through a coilbobbin, a plate shape auxiliary core positioned in contact with saidside legs of the fixed core and having an aperture at thepositionopposing to said center leg, a moving core formed to have asubstantially reverse U-shaped body part and lateral extensions at lowerends of both side legs of said body part, said moving core being freelyengaged in the aperture of said auxiliary core and being opposed withits upper surface of the body part to lower end surface of the centerleg of the fixed core, a carrier having a projection at the top forengaging inside the reverse U- shaped body part of the moving core and aplurality of openings at the lower part, a plurality of moving contactsrespectively including movable contacts provided at the respective ends,each of said moving contacts being passed through each of said openingsof the carrier and resiliently biased at the center against upper wallof the opening by means of a compression spring arranged at lower wallof the opening, a plurality pair of fixed contacts each having a contactto oppose to each contact of said moving contacts, a switching box forsecuring therein said pairs of fixed contacts and including a guidemeans for supporting slidably said carrier having the moving contacts,and a case enclosing the E- shaped fixed core and forming outer shellstructure together with said box as coupled thereto.

2. An electromagnetic contactor according to claim 1, wherein thecoupling position of said carrier to the moving core is provided with aspace between the top of the engaging projection of the carrier andupper wall of the reverse U- shaped groove of the core and a compressionspring is interposed in said space, thereby any inclined error of thecore is absorbed.

3. An electromagnetic contactor according to claim 1, wherein saidauxiliary core is provided at its outer periphery with a plurality .ofrecesses and at its inner periphery of the aperture with a plurality ofguide recesses, said outer peripheral recesses are adapted to engage aplurality of bosses provided at upper opening peripheral edge of saidswitching box and said inner peripheral guide recesses are adapted toreceive therein a plurality of projected stubs provided downwardly atthe lower surface of said coil bobbin.

4. An electromagnetic contactor according to claim 1, wherein insulativelocking means is interposed between said auxiliary core and uppersurface of said fixed contacts fixed in said switching box.

1 m v w I CENMPICAEE (30am "BL-0N r 3: 5 D March 21, 1972 ITNQR C01 (3)KIYOSHI YAMADA '1 I: is certified that error appears inflaeabove-identificd patent and that said Letters Patent are herebycorrected as shown below The l'n'ventorr'sname is incorrectly giveffl Itshould be: D

- KIYOSHI YAMADA Sig ned aqdQ s q ale'd 20th day .o'f 'Jx g ne. 1972,-

E L) Attest: I I H I. l h I WARD MILET HERMRH ROBERT GQTT SC HALK fizfiesting Offibe'ni Commigsippex of Patents r -wmrrwr f p m7. T Gain 1All A. L .411 O2 LORLLA A.

Pazcn: No. 3,651,437 Dated March 1972 :..v-.-.:Qr z KIYOSHI YAMADA I: iscertified that error appears in the above-identified parent :1 char.said Letters Patent are hereby corrected as shown below} The inventor.shame is incorrectly give nQ It should be: I

'.- KIYosHI YAMADA and thi R 9 (SEAL) 'Atcest: r EDWARD M.FLETQ}ER J.R.ROBERT QQ C Attescing O'ffiB'I'- 4 I s of Patents

1. In the electromagnetic contactor, the combination comprising E-shapedfixed core having both side legs longer than a center leg, a coil blockwound around said center leg of the E-shaped fixed core through a coilbobbin, a plate shape auxiliary core positioned in contact with saidside legs of the fixed core and having an aperture at the positionopposing to said center leg, a moving core formed to have asubstantially reverse U-shAped body part and lateral extensions at lowerends of both side legs of said body part, said moving core being freelyengaged in the aperture of said auxiliary core and being opposed withits upper surface of the body part to lower end surface of the centerleg of the fixed core, a carrier having a projection at the top forengaging inside the reverse U-shaped body part of the moving core and aplurality of openings at the lower part, a plurality of moving contactsrespectively including movable contacts provided at the respective ends,each of said moving contacts being passed through each of said openingsof the carrier and resiliently biased at the center against upper wallof the opening by means of a compression spring arranged at lower wallof the opening, a plurality pair of fixed contacts each having a contactto oppose to each contact of said moving contacts, a switching box forsecuring therein said pairs of fixed contacts and including a guidemeans for supporting slidably said carrier having the moving contacts,and a case enclosing the E-shaped fixed core and forming outer shellstructure together with said box as coupled thereto.
 2. Anelectromagnetic contactor according to claim 1, wherein the couplingposition of said carrier to the moving core is provided with a spacebetween the top of the engaging projection of the carrier and upper wallof the reverse U-shaped groove of the core and a compression spring isinterposed in said space, thereby any inclined error of the core isabsorbed.
 3. An electromagnetic contactor according to claim 1, whereinsaid auxiliary core is provided at its outer periphery with a pluralityof recesses and at its inner periphery of the aperture with a pluralityof guide recesses, said outer peripheral recesses are adapted to engagea plurality of bosses provided at upper opening peripheral edge of saidswitching box and said inner peripheral guide recesses are adapted toreceive therein a plurality of projected stubs provided downwardly atthe lower surface of said coil bobbin.
 4. An electromagnetic contactoraccording to claim 1, wherein insulative locking means is interposedbetween said auxiliary core and upper surface of said fixed contactsfixed in said switching box.